CD8A and hepatocellular carcinoma: The main types of stromal cells in the HCC microenvironment are hepatic stellate cells (HSCs), fibroblasts, endothelial cells (ECs), adipocytes, and immune and inflammatory cells – including CD8+ T cells, regulatory T cells (Tregs), macrophages, dendritic cells (DCs) and myeloid-derived suppressor cells (MDSCs) [12–15], and their complex interactions with HCC create a microenvironment suitable for tumor progression (Fig. 1).